This invention relates generally to electrostatographic reproduction machines, and more particularly to a low load fuser member, such as a roller, and a fusing apparatus and a color image reproduction machine, such as a copier or a printer, including same.
Reproduction machines such as copiers and printers typically employ the art or process of xerography. The art or process of xerography involves forming electrostatic latent images on a surface by first uniformly charging a photoreceptor. The photoreceptor comprises a charge retentive surface. The charge is image-wise selectively dissipated in accordance with an image pattern of activating radiation corresponding to an original image. The selective dissipation of the charge leaves a latent charge pattern on the imaging surface corresponding to the areas not exposed by radiation.
This charge pattern is then developed, or made visible with a development apparatus or unit containing developer material such as single component, or toner and other components including carrier particles. The toner is generally a colored powder which is charged and adheres to the charge pattern by electrostatic attraction resulting in a toner developed image. The toner developed image is then fixed to the imaging surface or is transferred to a receiving substrate such as plain paper to which it is thereafter fixed by suitable fusing techniques.
Black and white toner images can be formed by the process as described above, and multicolor toner images can be similarly formed by using not just one but several development units containing different colors of toner. Such multicolor toner images can be highlight color images or full color images. One approach for forming such toner images is in a single pass of the photoreceptor during which color separation toner images are formed in registration, one on another, or in what is called an xe2x80x9cimage-on-imagexe2x80x9d manner.
The final quality images produced or reproduced by image-on-image reproduction machines, depends in great part on quality fusing using a fuser roller in a fusing apparatus. A fuser roller and a fusing apparatus that are thermally efficient, and that can form a large or long fusing nip with as low a load as possible are desirable. In attempts to achieve large fusing nips under such conditions, conventional composite constructed fuser rollers have been proposed, having multiple layers of a fluoroelastomer, such as a copolymer of vinylidene fluoride and hexafluoropropylene known commercially as VITON A, or such as a terpolymer of vinylidene fluoride, hexafluoropropylene and tetrafluoroethylene, known commercially as VITON B. VITON A and VITON B and other VITON designations, are trademarks of E. I. duPont de Nemours and Company. Such conventional composite constructed fuser rollers also include for example, a conductive silicone base, a conductive flouroelastomer (VITON) interlayer and a thin top toner release layer of relatively insulative flouroelastomer (VITON).
Although some such conventional composite fuser rollers may be thermally efficient, they have been found to deficient in other respects due to the high hardness of the conductive flouroelastomer (VITON) layers which result in image quality defects such as xe2x80x9chaloxe2x80x9d and differential gloss. Further attempts to resolve such problems with such conventional fuser rollers tend to simply add costs, and normally to result in undesirably higher loads and strain energy.
There is therefore a need for a relatively low cost, thermally efficient and low load fuser roller, and a fusing apparatus including same, for use particularly in a color image reproduction machine to assure final color image quality.
In accordance with the present invention, there is provided a low load fuser member and fusing apparatus in a color reproduction machine for fusing high quality toner images onto an image carrying substrate. The low load fuser member for heating and fusing high quality toner images onto an image carrying substrate includes a soft, low durometer and thermally non-conductive first elastomeric material member for forming a relatively large fusing nip at a relatively low load; a second and thermally conductive elastomeric material forming an intermediate layer over the first elastomeric material member; and a toner image release layer formed over the intermediate layer for facilitating release of fused toner images.